Outside the convention center, an array of gun-control advocates is expected to demonstrate opposition to the NRA and its lobbying prowess.

"I don't think it's a losing battle at all," said Heather Ross, an organizer for the "Occupy the NRA" group that plans to lead the reading of names of 4,000 gun-violence victims under a #NoMoreNames banner at Discovery Green, across from the convention center. The list will start with the 26 victims of gunman Adam Lanza at Sandy Hook Elementary School in Newtown, Conn., last December.

Texas is not as uniformly pro-gun as most people believe, Ross insisted.

"The concept that we're all a bunch of gun-toting crazies is inaccurate," she said. "That's largely pushed by people elected to office."